Constantinople is generally regarded as the eastern empire. Constantine was never the bishop of Rome. In fact the Catholics still don't accept all the canons of some councils specifically because the Bishop of Rome had so little involvement.
Neither was Theodosius I (Constantinople I), Theodosius II (Ephesus), Marcian (Chalcedon), Justinian (Constantinople II), Constantine IV (Constantinople III) nor Irene (Nicea II). In other words, none of the Ecumenical Councils were called by a Patriarch at all.
While I'll agree that the last five of the councils were called by the rulers of the East, my purpose was to challenge your initial assertion that Rome (not the Patriarch, but Rome) historically did not call ecumenical councils.
With due respect, of course...